Chlorofluoroethanes such as 1,1,2,2-tetrachloro-1,2-difluoroethane (R-112), 1,1,2-trichloro-1,2,2-trifluoroethane (R-113) and the like have heretofore been used as solvent or detergent. These solvents have various excellent properties: they are nonflammable and low in toxicity to organisms; they can selectively solve fat, grease, wax and the like but do not attack plastics, rubber and like high molecular materials. However, R-113 and some chlorofluorocarbons are recently pointed out to be responsible for the destruction of the ozone layer in the stratosphere. The destruction of ozone layer will exert an adverse influene on the whole ecosystem including mankind. Thus, the use and production of chlorofluorohydrocarbons which may contribute to the destruction of the ozone layer are now restricted under international agreements and it is expected the use and production thereof would be totally banned.
Various compounds and materials have been proposed as solvents which may replace chlorofluorohydrocarbons. However, they have some defects and cannot fully satisfy the requirements as practical solvent. For example, chlorine containing solvents such as 1,1,1-trichloroethane, trichloroethylene, methylene chloride and the like are likely to cause environmental pollution. Alcohols and hydrocarbons are low in detergency and highly inflammable.